power on reset for digital circuits

[Sukhbinder]

H there all of u! i need a circuit to perform a power on reset for digital ics. i need something that is small ans simple using only simple discreet components like resistors,capacitors and transistor. no special ics please. the ic is a better choice but procuring it for me is a bit tricky here in INDIA. so i would really appreciate if u guys provided me with a simple solution.
thanks

 

[Staigen1]

Hi there Sukhbinder

Cmos or TTL?

//Staigen

 

[Sukhbinder]

Any thing that will work for both. I know about the working voltages for both TTL and CMOS but i still have to decide which type to use depending on their availability
thanx

 

[Staigen1]

Hi

A simple one, use schmitt-triggers
TTL: use a 7414 or similar, connect a 10K resistor to + and a electrolytic cap to ground

CMOS 4000 series: use a schmitt and a resistor to + and a cap to - or a resistor to - and a cap to +

//Staigen

 

[Sukhbinder]

Thanx